path: root/cpukit/dtc/README
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authorSebastian Huber <>2015-10-15 11:38:03 +0200
committerSebastian Huber <>2015-10-16 07:46:56 +0200
commit175263ec91f00f6668ae7f28f385850a1c77bf6b (patch)
tree096cc3d3b84671ffea8b3eedb2b89f0365bcd6e7 /cpukit/dtc/README
libfdt: Initial import
Import from: git:// Commit: 604e61e081e3c6c8fa1a8189c71cb3908a5bbc1e Date: 2015-09-29T09:09:08Z
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diff --git a/cpukit/dtc/README b/cpukit/dtc/README
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+The source tree contains the Device Tree Compiler (dtc) toolchain for
+working with device tree source and binary files and also libfdt, a
+utility library for reading and manipulating the binary format.
+DTC and LIBFDT are maintained by:
+David Gibson <>
+Jon Loeliger <>
+Mailing list
+The following list is for discussion about dtc and libfdt implementation
+Core device tree bindings are discussed on the devicetree-spec list:
+Home Page
diff --git a/cpukit/dtc/README.license b/cpukit/dtc/README.license
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+Licensing and contribution policy of dtc and libfdt
+This dtc package contains two pieces of software: dtc itself, and
+libfdt which comprises the files in the libfdt/ subdirectory. These
+two pieces of software, although closely related, are quite distinct.
+dtc does not incoporate or rely on libfdt for its operation, nor vice
+versa. It is important that these two pieces of software have
+different license conditions.
+As the copyright banners in each source file attest, dtc is licensed
+under the GNU GPL. The full text of the GPL can be found in the file
+entitled 'GPL' which should be included in this package. dtc code,
+therefore, may not be incorporated into works which do not have a GPL
+compatible license.
+libfdt, however, is GPL/BSD dual-licensed. That is, it may be used
+either under the terms of the GPL, or under the terms of the 2-clause
+BSD license (aka the ISC license). The full terms of that license are
+given in the copyright banners of each of the libfdt source files.
+This is, in practice, equivalent to being BSD licensed, since the
+terms of the BSD license are strictly more permissive than the GPL.
+I made the decision to license libfdt in this way because I want to
+encourage widespread and correct usage of flattened device trees,
+including by proprietary or otherwise GPL-incompatible firmware or
+tools. Allowing libfdt to be used under the terms of the BSD license
+makes that it easier for vendors or authors of such software to do so.
+This does mean that libfdt code could be "stolen" - say, included in a
+proprietary fimware and extended without contributing those extensions
+back to the libfdt mainline. While I hope that doesn't happen, I
+believe the goal of allowing libfdt to be widely used is more
+important than avoiding that. libfdt is quite small, and hardly
+rocket science; so the incentive for such impolite behaviour is small,
+and the inconvenience caused therby is not dire.
+Licenses such as the LGPL which would allow code to be used in non-GPL
+software, but also require contributions to be returned were
+considered. However, libfdt is designed to be used in firmwares and
+other environments with unusual technical constraints. It's difficult
+to anticipate all possible changes which might be needed to meld
+libfdt into such environments and so difficult to suitably word a
+license that puts the boundary between what is and isn't permitted in
+the intended place. Again, I judged encouraging widespread use of
+libfdt by keeping the license terms simple and familiar to be the more
+important goal.
+**IMPORTANT** It's intended that all of libfdt as released remain
+permissively licensed this way. Therefore only contributions which
+are released under these terms can be merged into the libfdt mainline.
+David Gibson <>
+(principal original author of dtc and libfdt)
+2 November 2007